Glaucoma

What is glaucoma?

Glaucoma is a disease of the optic nerve, which is the part of the eye that carries the images we see from the eye to the brain. The optic nerve is made up of many nerve fibers (like an electric cable containing numerous wires). Glaucoma damages nerve fibers, which can cause blind spots in our vision and vision loss to develop.

Glaucoma has to do with the pressure inside the eye, or intraocular pressure (IOP). When the clear liquid called the aqueous humor--which normally flows in and out of the eye--cannot drain properly, pressure builds up in the eye. The resulting increase in IOP can damage the optic nerve.

The most common form of glaucoma is primary open-angle glaucoma, where the aqueous fluid that normally circulates in the front portion of the eye is blocked from flowing back out of the eye through a tiny drainage system. This causes the pressure inside your eye to increase, which can damage the optic nerve and lead to vision loss. Most people who develop primary open-angle glaucoma notice no symptoms until their vision is impaired.

In angle-closure glaucoma, the iris (the colored part of the eye) may drop over and completely close off the drainage angle, abruptly blocking the flow of aqueous fluid and leading to increased IOP or optic nerve damage. In acute angle-closure glaucoma there is a sudden increase in IOP due to the buildup of aqueous fluid. This condition is considered an emergency because optic nerve damage and vision loss can occur within hours of the problem. Symptoms can include nausea, vomiting, seeing haloes around light, and eye pain.

Even people with "normal" IOP can experience vision loss from glaucoma. This condition is called normal tension glaucoma. In this type of glaucoma, the optic nerve is damaged even though the IOP is considered normal. Normal tension glaucoma is not well understood, but we do know that lowering IOP has been shown to slow progression of this form of glaucoma.

Childhood glaucoma is rare, and starts in infancy, childhood or adolescence. Like primary open-angle glaucoma, there are few, if any, symptoms in the early stage. Blindness can result if it is left untreated. Like most types of glaucoma, this type of glaucoma may run in families.

Your ophthalmologist may tell you that you are at risk for glaucoma if you have one or more risk factors, including elevated IOP, a family history of glaucoma, a particular ethnic background, advanced age, or certain optic nerve conditions. Regular examinations with your ophthalmologist are important if you are at risk for this condition.

Glaucoma: People of African Descent are at Risk
If you are of African ancestry, especially if you have a known family member with glaucoma, you are at risk for vision loss from this eye disease.

Glaucoma is a disease of the optic nerve, which is the part of the eye that carries the images we see from the back of the eye to the brain. The optic nerve is made up of many nerve fibers (like an electric cable containing numerous wires). Glaucoma damages nerve fibers, causing blind spots and loss of vision to develop.

Glaucoma has to do with the pressure inside your eye, or intraocular pressure (IOP). When the clear liquid called the aqueous humor--which normally flows in and out of the eye--cannot drain properly, pressure builds up in your eye. The resulting increase in IOP can damage the optic nerve.

Primary open angle glaucoma is the leading cause of blindness among people of African descent, occurring at a rate four times higher than among Caucasian patients. It also occurs about ten years earlier among people of African ancestry than among Caucasians, and develops more rapidly. Studies show that in the United States, people of African descent between the ages of 45-64 are approximately 15 times more likely to go blind from glaucoma than Caucasians with glaucoma in the same age group.

It is not clear why people of African ancestry have higher rates of glaucoma and subsequent blindness than Caucasians. One factor may be that African-Americans are more susceptible to developing elevated eye pressure (IOP) earlier in life, which is thought to contribute to optic nerve damage and eventual vision loss. Another reason may be that patients of African descent are less likely than Caucasians to have early eye examinations that may detect and treat glaucoma.

The best way to protect yourself and your family members against vision loss from glaucoma is by being aware of the higher risk of developing this disease, and by having regular eye examinations for glaucoma at appropriate intervals.

If you are at risk for developing glaucoma, you can help to protect yourself fro vision loss by having regular eye examinations for glaucoma at appropriate intervals. Recommended intervals for a comprehensive eye evaluation in people of African descent are:

Age 20-29: every 3-5 years
Age 30-64: every 2-4 years
Age 65+: every 1 to 2 years

If you are diagnosed with glaucoma, please make sure you tell your family members and urge them to have an eye exam for glaucoma. For more information on glaucoma: